Investigation of a laser scanner for measurement of lodging posture of a wheat bunch

A real time sensing technique for detecting lodging posture of crops was investigated using a laser scanner. In the laboratory experiment, posture profiles of a wheat bunch with four lodging directions (left, right, front, back) and three lodging angles (40°, 62°, 80°) were measured, and the profiles were assessed through comparisons with digital images. Also, inclination, skewness, and kurtosis were calculated using coordinate data of lodging profiles in three dimensions and the effectiveness of those values as indications representing lodging characteristics was assessed. As the results, the inclination of lodging posture was roughly detected for relatively large lodging angles. On the other hand, only upper profiles of a wheat bunch were measured under an upright condition and for the case that an angle of the sensor against a wheat bunch was not arranged appropriately. The limited profiles made it difficult to detect the inclination of lodging posture. Useful information on lodging characteristics, such as a lodging direction and density distribution of a wheat stalk, was obtained from values of skewness and kurtosis under certain conditions while the results were significantly affected by the setting for an angle of the sensor.